1. Field of the Invention
The present invention relates to a floor panel for an automobile. More particularly, the invention relates to a floor panel having a floor tunnel and a protrusion portion extending in a direction opposing a direction of the floor tunnel and crossing the floor tunnel which provides a rigid and lightweight floor panel.
2. Description of the Related Art
In the related art, a floor panel for a sedan or a wagon is formed by molding press of a thin steel sheet. A protrusion portion of the floor panel is provided at a center portion of the lateral length of a vehicle. The protrusion portion of the floor panel extends frontward and rearward from the center portion.
The protrusion portion for a front engine rear drive vehicle (FR vehicle) is fundamentally formed for passing a propeller shaft through the protrusion portion and is sometimes referred to as a floor tunnel. The propeller shaft is provided to transmit a driving force of an engine to a rear axle.
However, in a front engine front drive vehicle (FF vehicle), it is not necessary to provide the propeller shaft with the protrusion portion. In this case, the protrusion portion is formed for increasing the rigidity of the vehicle.
Further, the protrusion portion or floor tunnel is effective for taking a bending moment between the front and rear axles. However, since the floor tunnel does not ensure a sufficient rigidity of the floor panel in the transverse direction of the vehicle, the rigidity in the transverse direction is maintained by welding a cross member and a seat-rail mount portion, which are separately provided with the floor panel in the related art.
Therefore, the known structure of the floor panel including the welded cross member, the seat-rail portion, etc., makes it difficult to decrease a production process of the floor panel and the weight of the vehicle.